E34 525i M20 (89-91) Engines

See related information under Rebuilding: Engines and Turbos

Performance Computer Chips

Korman offers 4 basic rebuilding configurations:

• Stock
• Stage 1 and 2 Competition (not emissions legal due to inclusion of headers/cams)
• Stage 1 and 2 Clean Air Engines-Emissions legal-50 States
• Korman 2.7 Liter Stroker Engines(emissions legal variants available)
• Korman Competition Engines(not emissions legal due to inclusions of headers/cams)

Korman Stock Rebuilds

2 year/24,000 mile warranty

Our stock rebuilds are assembled to BMW specifications by our experienced and dedicated technicians rather than off a mass production assembly line. Korman engines are assembled with meticulous craftsmanship, precise machining, and detailed blueprinting. All of our boring is done with a torque plate for exceptional bore roundness and long engine life. These hand built engines are available at prices comparable to a factory reman units which offer only 12 month/12,000 mile warranties.

525i P/N 11036200

Korman Stage 1 Competition Engines

2 year/24,000 mile warranty

Korman Stage 1 Competition Engine-M20

Our Stage 1 rebuild will provide a moderate increase in power through the use of our proven performance techniques. Special valve and valve seat work, increased compression, Korman-Stahl Headers and Stage 1 cylinder head porting will net a gain of 12-25 HP depending on model. Performance computer chip suggested, not required.

525i P/N 11036510

Korman Stage 2 Competition Engine-M20

Our Stage 2 engines are designed for maximum performance without adversely affecting engine life or driveability. All Stage 2 Engines receive our flow testing porting and polishing, proven 3 angle valve seat work, back cut intake valves, dual valve springs, titanium retainers, Korman Rocker Arms, Korman-Stahl headers, and a Schrick 272 Camshaft (upgradable to a Schrick 288 on some models). M20 "i" engines receive our aluminum flywheel, while M20 "eta" engines receive our exchange lightweight flywheel. Korman performance computer chip suggested but not included.

525i P/N 11036350

Korman High Performance Clean Air Engines

2 year/24,000 mile warranty

Stage 1 High Performance Clean Air Engine-M20

In our Stage 1 Clean Air Engines we apply our high performance techniques to extract maximum power from stock parts while making no changes that affect Federal or State emissions laws. Our flow tested porting, polishing, valve and valve seat work promote smoother, more efficient air/fuel flow keeping the mixture better suspended for cleaner burning. Valve spring pressure is increased for a higher max rev limit of 7000 rpm. To reduce reciprocating weight and improve acceleration we lighten and balance the connecting rods, fit stronger light weight piston pins, and lighten the flywheel. These techniques produce a 10-15% power increase and an engine which revs much more quickly. Korman Performance computer chip suggested, not required.

525i P/N 110365C0

Korman Stage 2 Clean Air Engines

These engines receive our Stage 2 competition-type engine treatment for maximum emissions legal performance. Porting and polishing are more extensive than in our Stage 1 Clean Air Engine, and all valves are swirl polished. Also included are our titanium valve spring retainers, dual valve springs, Korman Rocker Arms, light weight steel alloy connecting rods, light weight piston pins and our lightened steel or aluminum flywheel (depending on model). Ceramic thermal barrier coating for the exhaust manifold and our special engine oiling system modifications are also provided. Special computer chip required.

525i P/N 11036350CA

Korman 2.7 Liter Stoker Engines

Our special conversions include a high performance 2.7L crankshaft and improved valve springs which allow safe revs to 6900 rpm. This conversion is available on all of our M20 Stock, Stage 1 and 2 Competition and Stage 1 and 2 Clean Air Engines. Call one of our staff for suggestions and pricing for any applications not listed.

• 2.7i Standard Engine P/N 11327200
• 2.7i Stage 2 Competition Engine P/N 11327350
• 2.7i Stage 1 High Performance Clean Air Engine P/N 113275CO
• 2.7i Stage 2 High Performance Clean Air Engine P/N 113276CO

Korman Race Engines

Whatever your series, whatever your specifications, Korman can build you a dependable, long lasting engine engineered for maximum power. Whether you need a reliable engine for BMW CCA Club Racing, or a 325 HP "conservative" race engine, call us first!

Korman Cylinder Heads

Korman cylinder heads are available prepared to the same specifications as described in our engine packages. If your engine is of moderate mileage and the bottom end is in good condition, then bolting on a Korman prepared cylinder head is a very economical and effective way of improving your engines' performance. Your cylinder head will be prepared by the same race engine technicians that build our winning race engines.

All Korman Cylinder heads are chemically cleaned, peened and inspected for flaws and warpage. No traces of old gasket material are left to spoil the sealing surfaces. New rocker shafts, rocker shaft clips and rocker arms are included, as are a cylinder head gasket set and Bosch spark plugs.

• Our Stock Heads use all stock BMW parts and receive special attention to valve train accuracy. Shipped pre-lubricated and ready to install. Stock replacement exhaust valves with oversized valve stems are included in our Stock Heads, since they are usually required at the time of rebuild.

• Our Stage 1 Heads include our flow tested porting and polishing, proven 3 angle valve seat work, back cut intake valves, and dual valve springs set for 7000 rpm limits. Eta engines include larger intake and exhaust valves.

• Our Stage 2 Heads receive more extensive porting, swirl polished valves, Korman Rocker Arms, titanium retainers and dual valve springs. Eta engines include larger intake and exhaust valves.

Korman M20 "i" Cylinder Head Rebuilds

525i Stock Cylinder Head Rebuild-P/N 11122036

525i Stage 1 Clean Air Cylinder Head Rebuild-Stage 1 porting, includes replacement exhaust valves and parts as listed above. P/N 11122136

525i Stage 2 Clean Air Cylinder Head Rebuild-Stage 2 porting, includes replacement exhaust valves and parts as listed above. P/N 11122236

525i Stage 2 Competition Cylinder Head Rebuild-As the Stage 2 above, also includes a Schrick 272 camshaft. P/N 11122336

Extrude Honed Intakes

The perfect compliment to your new cylinder head! The Extrude Hone process accomplishes porting and polishing throughout the complex BMW intake manifolds which are inaccessible by hand tools.

ALL 6 Cylinder P/N 13EXTRUDE01